1. Field of the Invention
The invention is related to a rotatable disc head for a floor treatment device, having a pair of coupling members which are pivotably connected to each other according to pivot axes which are transversely oriented with respect to each other, a rotation axis being defined which is transversely oriented with respect to said pivot axes, said coupling members being furthermore connected to each other by means of at least an elastically deformable connection element, wherein one of the coupling members includes fitting means for mounting said coupling member to the rotary drive of the floor treatment device and the other coupling member includes carrier means onto which a floor treatment element, such as a grinding disc, can be mounted.
2. Description of Related Art
Such a rotatable disc head is disclosed in GB-A-832321. The coupling members thereof are connected to each other through a ball joint which allows pivotal movements according to mutually perpendicular pivot axes. Furthermore, the coupling members are connected to each other through a centrally located helical spring. Said prior art rotatable disc head has the disadvantage that the ball joint has a limited torque capacity; moreover the centrally located spring, the purpose of which is to maintain a desired orientation of the ball joint components with respect to each other, has a limited capacity for redress of said components.
A further rotatable disc head is disclosed in EP-A-1985876. Said prior art rotatable disc head is provided with a universal coupling the coupling members of which are mutually connected through elastic dampers. Said elastic dampers are rigidly connected to both of the coupling members. As a result of these rigid connections, the elastic dampers are deformed not only in compression as is desired for obtaining the damping effect, but also in directions transverse with respect to the compression direction. As a result of these transverse deformations, undesired effects occur within the rotatable disc head. The pivots of the universal coupling are loaded by transverse forces as well, leading to vibrations and accelerated wear of both the universal coupling as well as of the elastic dampers.